With the rapid development of display technology, semiconductor component technology has made progress in leaps and bounds therewith as the core of a display device. As to existing display devices, the OLED (Organic Light Emitting Diode), as a current mode light-emitting device, is more and more applied in the field of high performance display, due to its characteristics of autoluminescence, quick response, wide angle of view, capability of being made on a flexible substrate, etc. According to the driving method, the OLED may be divided into two types: PMOLED (Passive Matrix Driving OLED) and AMOLED (Active Matrix Driving OLED). Since an AMOLED display possesses advantages of low manufacturing cost, high response rate, power saving, direct driving applicable to portable devices, large range of working temperature, etc., it is more and more applied in the field of high performance display.
However, in the process of using an AMOLED display for viewing a display image, a perception degree of human eyes may vary with a brightness of ambient light. For example, when the ambient light is relatively bright, it is necessary to turn up the brightness of the display so as to make the display image clearer; when the ambient light is relatively dark, it is necessary to turn down the brightness of the display to avoid the dazzling sense brought by the display image with higher brightness. Therefore, persons need to adjust the brightness of the display image according to different viewing environment.
In the prior art, a purpose of adjusting display brightness is achieved by adjusting the data voltage Vdata output by data line. In the process of adjusting a data voltage, firstly a grayscale value is converted to a brightness value by way of lookup table, according to Gamma curve (e.g., Gamma 2.2), and then gain computation of corresponding times is applied to the brightness value, thereby adjusting the brightness value. In order to display the brightness-adjusted image, it is further required to convert the adjusted brightness value to a grayscale value by way of lookup table according to the Gamma curve, and then the grayscale value is input to every pixel circuit through data line. In summary, the above method requires a number of lookup steps in the process of brightness adjustment, therefore it is required to add numerous storages. Accordingly, many FPGA (Field-Programmable Gate Array) resources are taken up, increasing a cost of production.